Steam boiler



Jan. l5, 1946.

W. E. TIEMEIER STEAM BOILER Filed Aug. 4, 1944 4 Sheets-Sheet 2 QN N .mW w MY www MN, k Nv NN Sv Wma;

4 Sheets-Sheet 3 STEAM BOILER W. E. TIEMEIER Filed Aug. 4, 1944 Jan.15,1946.

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Patented Jan. 15, 1946 UNITED STATES PATENT OFFICE y STEAM BOILER WalterE. Tiemeier, Burlington, Iowa, assigner to Murray Iron Works Company,Burlington, Iowa, a corporation of Iowa Application August 4, 1944',Serial No. 547;!)96

9 Claims.

My invention relates to steam boilers.

An important object of the invention is toI provide a steam boiler whichis compact and highly eioient in operation.

A further object of the invention is to provide water tubes for coolingthe Walls of the furnace section whereby the. heat is reduced before itenters the boiler section, and the eicieney of the steam boilerincreased.

A further object of the invention is to provide bank or banks of Watertubes WithinA the boiler section which will absorb practically all ofthe heat. generated and also permit of the free travel of the heatedgases.

A further object of the invention is to provide a bank or banks of Watertubes and baiiles, arranged W-ithin the boiler section, for causing theheated gases totravel through a long path, While contacting with theWater tubes, the arrangement of the Water tubes andv baiiies beingsuch'v that the gases are free to travel through the elongated passageWithout the assistance of an induced draft.

A further object of the invention is to provide a steam boiler, thesmall sizes kof which are adapted to be assembled as complete units forso-called package shipments, asV far as shipping clearances andequipment will permit.

Aiurther .object ofthe invention is to provide a steam boiler having twoside water headers having flatinner faces which take-the place ofrefractoriessothat no trouble Willfbe experienced due to the brasion ofthe refractories or clinker adherence to such refractories.

A further object of the invention is to providev side water headers ofthe above mentioned'character havin-g flat `sides which are connectedwith stay bol-ts so thatr the headers may -be satisfactorily used Withsteam boilers of `all but extremely high pressures.

A further object .of the inventionis to provide side Water headershaving inner flat faces' and being ofy suiicient areas to extendabovethe fuel bed so that molten ash. which at times may adhere to thesewater cooled ila-t faces,.may be removed therefrom by reducingy capacityoperations when permissible,V which will cool the ashl and such ash willthen solidify and the resulting ash slag-Will automaticallyy fall fromthe water cooled faces into the fuel bed'so that the traveling ordumping. grate will discharge the saine into the ash pit.

Other objects andadvantages of theinvention inthe accompanying drawingsforming a part ofthis application and in which like numerals are Figurefi ifs asimilar View taken on line 4-4` of Figure 1 with. the iront Walltubesv omitted;

Figure 5 is asimilar View taken on line li-50iy Figure 1, and

Figure 6 Ais a similar View taken on line l-.G'of' Figure .1. Y

In the drawings,.wherein for the purpose oi illustration is shown .apreferred embodiment of my invention, the numeral .I0 designates afoundation whichlmay'be formed ofvconcrete or the like and includesabottom Il, sides I2, a forwardlend I3 and rear end Ill'.Disposedbetween the ends I3 and I4-aretransverse Walls or bridges .landI6as shown. The steam boiler casingwhich `is mounted uponthe foundationI Il is'formed .of refractory and heat insulating material andvcomprisessides I1, aViorwardiendV I8 and-a rearend I9. The sides II arecurved/and converge in-` wardly at their upper ends tovform atoporarch2li, having. a central longitudinal4 opening 2l formed therein; for apurpose-to be described,- Surrounding-the. refractory casngis a. jacket.22-l formed or metal, andthis `jacket is yformed vin seotions securedtogether by'jacket supports 212 Arranged within the opening ZIis-an-upper central longitudinal water and steamy 23;

which enter-ids.y throughout the entire length-o the steam-boilercasingand-projects beyondythef4 This' centrall water vand steam-drum iscovered by heat insulat-f forward f andl rear endsY l8- and I9.

ingv material 24.

The numeral 25 designates side 'water .headers,v whichvextendthroughoutthefentire .length of'lthe steam'boiler cas-ing.- EachWater header i25=isrecf tangular in-cross section and lincludesahorizontal bottom 26j, avertcal outer sidel, averticalinner" side 28,vupper horizontal topisection'ZfS, v-anclaisi inclined or .diagonal top:sectioncBa `The water' header 25 is partlyy .embedded Iwithin the. sideI?! f and is-arranged within the recess I tori-ned with# in the side and`projectsinwardly,beyond the inner face of the sideI'l; The recesstoropening-113Mo):-

tends throughoutthe lentlre-ler-igth' of the side 2131 and the-side. issupported Lbytheitop' section -291 The water header-25 has itssbottom'ZG; :estingK upon the' side l2.. The-:heat insulating material'32 may be arranged between the outer side 21 and the jacket 22.Attention is called to the fact that the sides 21 and 28 on the headerare vertical and parallel and that the inner side 28 is disposed withinthe furnace section 33 and defines the sides of the lower or fuel bedholding portion of this furnace section. The header 25% is formed ofmetal and the sides 21'and 28 are connected by stay bolts 34, These staybolts retain the sides 21 and 28 parallel. The headers are suicientlystrong forV use with all types of steam boilers excepting those ofextremely high pressure.

The numeral 35 designates an upwardly extending vertical baffle orbridge, defining the rear end Y of the furnace section 33. This upwardlyextending baille 35 terminates shortof the water and steam drum 23providing an opening 35, for the products of combustion. At the rear ofthe baille or bridge 35V is a downwardly extending vertical baillev35,"extending from the top 29 and terminating short of the lower end ofthe baiiie 35 to provide an opening 31. At the rear of the baille 3IfV'is a vertical bailleeextending upwardly, and terminating short of thetop to provide an opening 38. At the rear of the baille 36a is avertical bafile 39, extendingdownwardly from the topl and terminating atits lower end short of the lower end of the baille 36a to provide anopening 39'. The space between the baie'35 and the rear'rend I9constitutes a boiler section 39a, and the several -baiiles coact toprovide a long tortuous passage within the boiler section for the heatedgases or Yproducts of combustion. These heated gases discharge throughan opening 40 to a suitable stack or the like.

f Arranged adjacent to or in thermal contact with'eachside I1 in thefurnace section, is a longitudinal row of vertical water tubes 43, whichserve/to cool sides I1. At their lower ends, the water tubes l43 in eachrow are attached to the top section 29 of the corresponding header 25and communicate with the interior of the header. Thevvertical tubes 43in each row are bent so that they Amayexpand without disrupting theirconnections' and alternate tubes 43 are bent to form upper Yportions 44,whileA the remaining alternate rtubes l43 are bent to form-upperportions 45.V "The:A upper portions 44 closely follow the contour of thetop 20 VwhileY the *upper portions; 45 are spaced downwardly from thesame, The Yupper portions 44 andf45 are secured to the 23,-'in staggeredrelation so that the drum is notunduly weakened and need not be formedo'fAunnecessarily heavy material. 'I'he upper portionsf44 and 45 of`course communicate with the interior of the water and steam drum 23. Thelongitudinal rows of vertical tubes- 43 are confined within the furnacesection 33` and are arranged in 'relatively close relation and contactwith the sides to screen or cool sides I1. These water tubes 43 areentirely uncovered. The forward end tubes 43 also extend across theinner face of the end I8 and additional vertical water tubes 45, 41,wand 49, also extend across the inner face of the end I8. The water tube46 is attached to the diagonal top section 30 of the header 25, whilethe water tubes 41, 48 and 49 are attached to the vertical side 28.These water tubes arebent near their upper and lower ends and at theirupper ends they are attached to the water and steam drum 23 at spacedpoints and are disposed in the same transverse tending across the end\|8, have thermal contact" therewith and serve' to' co'ol the end I8."The rear 'water tube 43 attached to each header 25 extends across thebaille 35 and vertical tubes 50, 5|, 52 and 53 also extend across thebaille 35 and are connected with each header 25. The water tubes 5D, 5I,52 and 53 are bent at their lower ends. The tube 50 is attached to thediagonal top section 30 and the tubes 5I, 52 and 53 are attached to thevertical side 29. All of these tubes lead into the interior of theheader 25. The tubes 50, 5 I, 52 and 53 are bent at their upper ends andthese upper ends are attached to the water and steam drum 23, at spacedpoints and lead into the drum 23. The upper ends of the tubes 5U, 5I, 52and 53 are disposed in the same transverse vertical plane. It is thusseen that the two sets of tubes 43, 5B, 5I,

Y 52 and 53, having thermal contact with the baille distance than thetubes 43.

35, serve to cool the same. The vertical water tubes support the waterand steam drum.

Arranged within the boiler section 39a at the rear of the baille 35 is abank of vertical tubes 54, 55, 55, 51 and 58. These tubes are arrangedin longitudinal and transverse rows. In the longitudinal rows the tubesare spaced a greater In the transverse rows the tubes are spaced thesame distance as the spacing of the transverse rows of tubes whichextend along the end i8 and balile 35. The longitudinal rows of tubes 54extend along the sides Y' I1 in the furnace section 39a and have thermaland communicates with the interior of the header.

The tubes 55, '55, 51 and 58 are bent at their lower ends. rI'he tube 55is attached to the diagonal top section 30 while the tubes 56, 51, and58 are attached to the vertical side 28 and these tubes all communicatewith the interior of thev header 25. The tube 54 is bent at its upperend and is attached to the water and steam drum 23, and also the tubes55, 56, 51 and 58 have their upper ends bent and are attached to thedrum 23. All of these tubes communicate with the interior of the drum.Their upper ends are disposed in the same vertical transverse plane` Thebaffles 35', 35a, and 38 are arranged between certain of the transverserows of boiler section tubes 54, 55, 56, 51 and 58, to provide a longzig zag passage for the heated gases and these tubes and the verticalwater tubes within the furnace section 33 absorb practically all of theheat generated before these gases discharge through the opening 46.

In the boiler section 39a, the side headers 25 are preferably connectedby horizontal water tubes 59, arranged between the transverse rows ofvertical water tubes.

The bottom II has a bridge 60 at the rear of which is an ash pit 6Ihaving an ash removal door 62. One or both side Water headers may beprovided with an entry passage 53 formed by a tube and covered by asuitable door. This passage is arranged near and above the ash pit 5I.The forward end I 8 has an opening V54 between its lower end andthebridge 60 and this opening extends throughout substantially theentire width 0f the forward end I 8.

The numeral 55 designates endless chain grate elements of a chain gratestoker. These endless chain grate elements are supported by sprocketwheels 55' and B5. The sprocketwheels S5' are-disposed exteriorly of thefurnace section 33 while the sprocket wheels 5S are arranged within thefurnace section over the Yash pit 6I.

The endless chain grate elements are. driven lin theusualmanner so thattheir upperlruns travel rearwardly as indcatedby the arrows The endlesschainv grate elements extend. through the transverse opening 64 andaresuitablyspaced from the top wall of the opening Gilfto provide apassagefor the fuel 63', supplied from, a hopper ParticularV attentionis calledy to the factrthat the endless chain grate elements arearrangedin close relation to the inner vertical sidewalls 28 ofthe sidewall headers 25. The inner Vertical walls 28- extend only to the-leveloftheupper runs ofA the endless chain grate'- elements while they-extendabove the upper runs of the said grate elements and above the bed-loflfueliifor a considerable distance. The side-water headers and the upperruns of the endless chain Vgrate elements therefore constitute afuelbedholding portion. The fuel bed therefore contacts withthervertical walls 28` of the side water` headers andvnot with therefractorysideslff. During the operation of the boiler the moltenashwilladhere to the inner vertical wall-2S and this moltenA ash v may beremoved by reducing capacity operations Whenpermissible, which will coolthe molten ash and such ash will then solidify and the resultant ashslag 69 formed upon the watercooled vertical metal wall 28 willautomatically fall from thevertical water cooled surface into the fuelbed so that the grate, traveling or dumping, will discharge the ash slaginto the ash pit.

It is to be understood that the invention is not restricted to the useof a chain grate stolier and that other types of stokers may beemployed. I may employ a stoker having a dumping grate with mechanicalmeans to push the fuel rearwardly along the grate. Whenvthis forincfStoker is used the grate is arranged near the bottom of the side waterheaders, in the position occupied by the upper runs of theendless'ch-ain grate elements 65; so that the side water headers will.projetfor substantial distances above the fuel bed carried by the grate.I-`also contemplate using a grate without the Stoker feature, in whichevent the grate will be arranged near the-lower ends of the side waterheaders. YThe invention is not necessarily restricted to the useof'solid fuel requiring grates, asv I contemplate using powdered solidfuel or oil. In this event, a burner noazle would extend through asuitable opening formed in the forward end i3, andthe large openingrflwould be dispensed with. The forward end It may be provided with anysuitable number and arrangement of openings, depending uponvthe type offuel handling apparatus to be used, The water tubes which extend overthe end` Ito cool the saine, will be suitably 'shaped or bent'l toaccommodate themselves to these openings, or some of these tubes may beomitted. In some circumstances, Ythewater tubes which contact with theforward-end IS andthe baffle 35 to cool the same', may be dispensedwith.

The operation ofthe the steam boilerfis as follows; The vfuel isburnedwithin the furnace section 33 jand the longitudinal rowsoftubesllreducehthe temperature and cool the'jsides l1. The water tubescontacting with the forward end laandbaiile 35 also cool these parts andfurther reducethe temperature. The heatedgases, at a somewhat reducedtemperature, l now'V travel through melone Zie Zag passage pliedued bythe baiilesgvand heat exchange is effectedjwith the Water the banlsof.'Wetel; tubes Llflths b'oiler:

section.v The fuel bed upon the rate vcontacts with the inner verticalwater cooled metai walls 28and not withthe refractory sides: 1.1 Asaresult of this no trouble will he experienced due to the abrasion oftherefractories "or clinler 'ad-A herents to'such refractories. When thevmolten ash adheres to the ilat verticalwater cooled walls zzthe samemay-be removedthereiro'm by reducing capacity operations whenpermissible, which will cool the ash and such ash willthen-solidify andthe-.resultant ash slagfwiil automatically drop from the wall 28 intothe fuel beda. This slag will be discharged into the ash pit bytheaction ofthe gratev which may be of the traveling or dump type. f

It is tor-be understood that the formvof in vention herewith shown anddescribedv is y to lbe taken as a preferred' example of the-same andthaty various changes in the shape, size and arrangement of lparts maybe resorted to without departing from the spirit of my invention or thescoperof the subjoined claims.

Having thus described my invention, what I claim-is:

l. In a steam boiler, a casing formed ofrefractory material,V meansV todivide the casing into a furnace section and a boiler sectioni an upper'central longitudinal water and steam drum extending throughoutsubstantially the entire length cf the'casing, side water headers havinginner substantially vertical and substantially flat sides,l the headersextendingthroughoutsubstantially theentire vlengthofthe casing, aD grateare ranged Within the furnace section-and-dlsposed between the innersubstantially'yertical sides of theheaders, said side water headershaving their bottomsA arranged generallyl atthe elevation of the-uppersurface of the grate sothat such headers pro-jectabove the upper surfaceof theg'rate throughout the major portion of their vertical dimensions,said grate andfside waterheaders constituting deep means for holding afuel bed and retaining the same out of contact withthe refractory sidesofAv the casing,A longitudinal rows of upstanding water 4tubes arrangedwithin the furnace section and disposedadiacent'tothe sides of thefurnace section to cool the same and -havingftheir lowerl ends connectedwith the side waterY headersand their upper lends connected with thewaterand steain'drum, and a bank 'ofu upstandi-ng tubes arranged withinthe boiler section and connected a'ttheirlower ends wi-tnthe side waterheaders andv atgtheir upper endswith the water and steam drum. I

2. In a steam boiler', a casing formed ofrefractory material, meansto-divide the casing into a furnace section and a boilergsection", anupper central longitudinal water and steam drum extending throughoutsubstantially the entire length of the casing, side water headers havinginner substantially vertical and su'jr'ist'an tially'flat sides, theheaders extending throughout substantially the entire lengthl ofthecasing, said headers being arranged within the lower portion of the`furnace section and havingtheir inner substantially vertical andsubstanti'allyatsides arranged for contact with-the fuel bed,*a gratearranged Within the furnace section between the inner substantiallyvertical sides of the headers to support the fuel bed; saidheadershaving a much greater Vertical transverse dimension thanhorizontal transverse' dimension and projecting above'theupper surfacecf the'grate throughout the major portion ofthe vertical dimensionsfofsuch headers so that the fuel bed 'is retained ou'tl of lcontact withthe refractory sides ofthe fur'- nace section, longitudinal rows of:upstanding water tubes arranged within the' furnace section nacesection to cool the same land having their lower ends connected with theside water'headers and their upper ends connected with ,the water andsteam drum, anda bank of upstandina' Water tubes arranged within theboiler section and connected at their lower ends with the side waterheaders and at their upper ends with the waterVand steam drum. i

3. In a steam boiler, a casing formed of refractory material, saidcasing having a furnace section and a boiler section, an 'upper centrallongitudinal Water and steam drum extending throughout substantially theentire length of the casing, side water headers which are substantiallyvrectangular in transverse vertical section arranged within the lowerportion of the casing and extending throughout substantially the entirelength of the casing, said headers having inner substantially verticalandsubstantially Vfiat sides, an endless chain grate device arrangedwithin the furnace section between the inner substantially verticallysides of the headers to support the fuel bed and more the samerearwardly said headers having a considerably greater verticaltransverse dimension than horizontal transverse dimensionV and havingthe major portions of theirA vertical dimensions arranged above theupper face of the endless chain grate, the inner substantially verticalsides of the headers contacting with the fuel bed and extending abovethe same to retain the fuel bed out of contact with the refractory sidesof the furnace section, longitudinal rows of upstanding water tubesarranged within the furnace section and disposed adjacent to the sidesof the furnace section to cool the same and'having their lower endsconnected with the side water headers and their upper ends connectedwith the water and steam drum, and a bank of upstanding water tubesarranged within the boiler section and connected at their lower endswith the side water headers and at their upper ends with the water andsteam drum.

4. In a steam boiler, a casing formed of refractory material, saidcasing including sides, a forward end and a rear end, a baille arrangedwithin the casing to form therewith a furnace section and a boilersection, an uprper central longitudinal water and steam drum extendingthroughout substantially the entire length of the casing, side waterheaders which are rectangular in vertical cross section arranged withinthe casing and extending throughout substantially the entire length ofthe casing, each header comprising inner and outer substantiallyvertical sides the inner sides being substantially flat, aYsubstantially horizontal top section and a substantially horizontalbottom, each header being embedded within the lower portion of therefractory side of the casing and projecting inwardly beycnd such side,a grate arranged within the furnace section between the innersubstantially vertical and substantially fiat Ysides of thel headers tosupport the fue1 bed, the headers extending above the grate for themajor portion of/their vertical dimensions, longitudinal rows ofupstanding water tubes arranged within the furnace section and disposedadjacentto the sides and disposed adjacent to the sides of the furof thefurnace section to cool the same and having their lower ends connectedwith the substantially horizontal topsections ofthe headcrs'and steamdrum, and a bank of upstandlng water tubes arranged within the boilersection and connected at their lower ends with the side water headersand at their upper ends with the water and steam drum.

5. In a steam boiler, a casing formed of refractory material, saidcasing including sides, a forward end and a rear end, a baiile arrangedwithin the casing to form therewith a furnace section and a boilersection, an upper central longitudinal water and steam drum extendingthroughout substantially the entire length of the casing, side waterheaders arranged within the lower portion of the furnace section andwithin the lower portion of the boiler section and extending throughoutsubstantially the entire length of the casing, each header comprisinginner and outer substantially vertical sides, the inner substantiallyvertical sides beingsubstantially flat a substantially horizontal topsection and a substantially horizontal bottom, each header beingembedded within the refractory side of the casing and projectinginwardly beyond such side, a grate arranged within the furnace sectionbetween the inner substantially vertical sides of the headers, saidheaders having the major portion of their vertical dimensions arrangedabove the upper surface of the grate, the substantially vertical sidesof the headers extending above the grate for a substantial distance. alongitudinal row of upstanding water tubes arranged within the furnacesection and disposed in substantial contact with each refractory side ofthe furnace section to cool the same, the tubes in the longitudinal rowbeing arranged in close relation and having their lower ends connectedwith the substantially horizontal topsection of the header, the tubes inthe longitudinal row having their upper ends disposed in two groupshaving different elevations so that such upper ends are staggered, theupper staggered ends being connected with the water and steam drum, anda bank of upstanding water tubes arranged within the boiler section andconnected at their lower ends with the side water headers and at theirupper ends with the water and steam drum. Y

6. In a steam boiler, a casing formed of refractory material, saidcasing including sides, a forward end and a rear end, a baffle arrangedwithin the casing to form therewith a furnace section anda boilersection, an upper central longitudinal water and steam drum extendingthroughout substantially the entire length of the casing, side headersarranged within the casing and extending throughout substantially itsentire length, the side headers being disposed within the lower portionof the furnace section, each header comprising inner and outersubstantially vertical sides, the inner side being substantially fiat, asubstantially horizontal top section and a substantially horizontalbottom, each header being embedded within the refractory side of thecasingand projecting inwardly beyond such side, a grate arranged betweenthe inner substantially iiat faces of the headers,V said headers havinga considerably greater transverse vertical dimension than transversehorizontal dimension and projecting above the grate throughout the majorportion of their vertical dimensions, a longitudinal row of upstandingwater tubes arranged within the furnace section and disposed insubstantial contact with each refractory side of the furnace section tocool thesame, the tubes in Y the longitudinalrow being arranged in closerelation and having their lower ends connected with the substantiallyhorizontal top section of the header, the alternate tubes in thelongitudinal row having their upper ends staggered and connected withthe water and steam drum, and a bank of upstanding tubes arranged withinthe boiler section and connected at their lower ends with the innersubstantially vertical sides of the side water headers and at theirupper ends with the water and steam drum, the tubes in the bank beingspaced sufficient distances apart so that the heated gases will travelthrough the boiler section without an induced draft. l

7. In a steam boiler, a casing formed .of refractory material, saidcasing including sides, a forward end and a rear end, a baiile arrangedwithin the casing to form therewith a furnace section and a boilersection, an upper central longitudinal water and steam drum extendingthroughout substantially the entire length of the casing, side headersarranged within the casing and extending throughout substantially itsentire length, the side headers being disposed within the lower portionof the furnace section, each header comprising inner and outersubstantially vertical sides, a substantially horizontal top section anda substantially horizontal bottom, each header having a considerablygreater vertical transverse dimension than horizontal transversedimension, each header being embedded within the refractory side of thecasing and projecting inwardly beyond such side, a longitudinal row ofupstanding water tubes arranged within the furnace section insubstantial contact with each refractory side of the furnace section,the tubes in the longitudinal row being arranged in close relation andhaving their lower ends connected with the substantially horizontal topsection of the header, the alternate tubes in the longitudinal rowhaving their upper ends staggered and connected with the water and steamdrum, a transverse row of upstanding Iwater tubes arranged within thefurnace section and substantially contacting with the forward end of thecasing and having their lower ends connected with the innersubstantially vertical sides of the side headers and their upper endsconnected with the water and steam drum, a transverse row of upstandingwater tubes arranged within the furnace section and substantiallycontacting `with the baille to cool the same and connected at theirlower ends with the inner substantially vertical sides of the headersand at their' upper ends with the water and steam drum, and a bank ofupstanding tubes arranged within the boiler section and connected attheir lower ends with the inner substantially vertical sides of theheaders and at their upper ends with the water and steam drum.

8. In a steam boiler, a casing formed of refractory material, saidcasing including sides, said casing having a furnace section and aboiler section, an upper central longitudinal water and steam drum forthe furnace and boiler section, side water headers for the furnace andboiler sections, the side lwater headers being disposed within the lowerportion of the furnace and boiler sections, each header comprising innerand outer substantially vertical sides, stay bolts connecting the sides,each header having its inner side uncovered, each header having vaconsiderably greater vertical transverse dimension than horizontaltransverse dimension, a longitudinal row of upstanding water tubesarranged within the furnace section in substantial Contact with eachrefractory side of the furnace section, the tubes in each row havingtheir lower ends connected with the substantially horizontal top of theacljacent side water header and their upper ends connected with thewater and steam drum, and a bank of upstanding water tubes in the boilersection, including two groups of such tubes, one group of such tubeshaving their lower ends connected with the substantially vertical innerside of one side water header and their upper ends connected with thewater and steam drum.

9. In a steam boiler, a casing formed of refractory material, saidcasing including sides, said casing having a furnace section and aboiler section, an upper central longitudinal water and steam drum, sidewater headers arranged within the casing, each side water header havinga substantial vertical dimension and including parallel vertical innerand outer sides, stay bolts connecting the sides, each header having itsinner side uncovered, a longitudinal row of upstanding water tubesarranged within the furnace section in contact with each refractory sideof the furnace section and having their lower ends connected with thesubstantially horizontal top of the adjacent header and their upper endsconnected with the water and steam drum, an upstanding bank of watertubes within the boiler section having their lower ends connected withthe substantially vertical inner faces of the headers and their upperends with the Water and steam drum, a grate arranged between thesubstantially vertical inner faces of the headers and having its upperface disposed at approximately the elevation of the bottoms of theheaders, and transverse horizontal tubes arranged within the boilersection and connected with the side headers.

WALTER E. TIEMEIER.

